One of the challenging things about debugging an AJAX application is that it isn't obvious how to view the html source that is being rendered by the browser after you have made modifications to it via an AJAX callback.  If you use the browser's built-in View Source command then it will show you the source that was used to render the original page, but it will not include any modifications made via javascript/AJAX calls.

To figure out how to view the generated source I turned to Google and found Rumen Stankov's post on telerik blogs. 

If you are trying to view the generated source in Firefox, the simplest way is to first download and install the Web Developer extension.  Then go to the View Source menu item and select "View Generated Source".

To view the generated source in IE you can type the following in the address bar

javascript:'<xmp>' + window.document.body.outerHTML+ '</xmp>'

Or you can use this bookmarklet (Drag to links bar or add to Favorites): View Generated Source